11.4Dynamic Type (iOS) and Font Scaling (Android)

Users who increase system font size must not be punished with broken layouts. This is both an accessibility requirement and a legal obligation.

def test_dynamic_type_does_not_break_layout(driver):
    """App must remain usable at largest dynamic type setting."""

    # Set accessibility font scale to maximum
    if driver.capabilities["platformName"] == "iOS":
        # iOS Dynamic Type: AX_EXTRA_EXTRA_EXTRA_LARGE
        driver.execute_script("mobile: configureLocalization", {
            "accessibilityPreferences": {
                "preferredContentSizeCategory": "UICTContentSizeCategoryAccessibilityExtraExtraExtraLarge"
            }
        })
    else:
        # Android: maximum font scale is typically 2.0
        driver.execute_script("mobile: shell", {
            "command": "settings",
            "args": ["put", "system", "font_scale", "2.0"]
        })

    # Navigate through critical screens
    screens = ["home", "search", "product-detail", "cart", "checkout"]
    for screen_id in screens:
        driver.find_element(AppiumBy.ACCESSIBILITY_ID, f"{screen_id}-tab").click()

        # Verify no text is clipped (truncated with ...)
        text_elements = driver.find_elements(AppiumBy.CLASS_NAME, "XCUIElementTypeStaticText")
        for text_el in text_elements:
            label = text_el.get_attribute("label") or ""
            # Check that critical text is not truncated
            assert not label.endswith("...") or len(label) > 20, \
                f"Text appears truncated at large font: '{label}' on {screen_id}"

        # Verify no overlapping elements
        all_rects = [el.rect for el in text_elements if el.is_displayed()]
        for i, r1 in enumerate(all_rects):
            for r2 in all_rects[i+1:]:
                overlap = (
                    r1["x"] < r2["x"] + r2["width"] and
                    r1["x"] + r1["width"] > r2["x"] and
                    r1["y"] < r2["y"] + r2["height"] and
                    r1["y"] + r1["height"] > r2["y"]
                )
                if overlap:
                    overlap_area = (
                        min(r1["x"]+r1["width"], r2["x"]+r2["width"]) - max(r1["x"], r2["x"])
                    ) * (
                        min(r1["y"]+r1["height"], r2["y"]+r2["height"]) - max(r1["y"], r2["y"])
                    )
                    assert overlap_area < 100, \
                        f"Significant element overlap detected on {screen_id} screen"